Circuit interrupter with improved venting means



F. 1.. GELZHEISER 3,283,102

CIRCUIT INTERRUPTER WITH IMPROVED VENTING MEANS Nov. 1, 1966 Original Filed Aug. 25, 1960 2 Sheets-Sheet l 1966 F. L. GELZHEISER 3,

CIRCUIT INTERRUPTER WITH IMPROVED VENTING MEANS Original Filed Aug. 25, 1960 2 Sheets-Sheet United States Patent 4 Claims. (Cl. 200-144) This application is a division of the copending application Serial No. 51,963, filed August 25, 1960.

This invention relates to electric circuit breakers and more particularly to manually and automatically operable circuit breakers for controlling small and moderate power electric circuits.

An object of this invention is to provide a duplex circuit breaker with improved means for exhausting arc gases from either or both of the compartments of the breaker.

Another object is to provide an improved dependable duplex circuit breaker which is relatively inexpensive and easy to manufacture and assemble.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description when read in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side elevational view of one of the interrupting units of a circuit breaker embodying the principal features of the invention. The interrupting unit is shown in the closed position;

FIG. 2 is a view similar to FIG. 1 except that the parts are shown in the open position;

FIG. 3 is a side elevational view of the other interrupting unit of the duplex circuit breaker, the parts being shown in the tripped position; and

FIG. 4 is an end view, on a smaller scale, of the assembled duplex circuit breaker.

Certain features of the circuit breakers of this invention are described and claimed in the patents to Francis L. Gelzheiser, Patent No. 3,088,008 and Patent No. 3,110,786.

Referring to FIG. 4 of the drawings, a duplex circuit breaker indicated generally at 9 includes an insulating housing which is composed of two parts, 11 and 13, forming two compartments. Each of the parts 11 and 13 is composed of a back portion molded integral with four sides forming an open front. The open front of the part 11 is covered by the back portion of the part 13, and the open front of the part 13 is covered by a cover 15. The three housing parts 11, 13 and 15 are held rigidly together by three rivets 17 (FIGS. 1-3).

The housing parts 11 and 13 form two independent compartments housing two circuit interrupting units which, except for a line terminal structure that will be described later, are of substantially identical construction and operation, each, for most applications, operating independently of the other. FIGS. 1 and 2 illustrate the closed and open positions respectively of the circuit interrupting unit housed in compartment 13 (FIG. 4). The tripped position of the interrupting unit of the compartment 11 is shown in FIG. 3. The interrupting units illustrated in FIGS. 1-3 are different units in order to more clearly illustrate front mounting means which will be hereinafter described. Since the operation of both of the interrupting units and all of the parts except those that are specifically mentioned to be otherwise are alike, like parts are shown with like reference characters, and the description of the operation of the mechanism of only one of the interrupting 3,283,102 Patented Nov. 1, 1966 units can be applied, unless otherwise mentioned, to both of the units of the duplex circuit breaker.

Referring to FIG. 1 of the drawings, the circuit interrupting unit shown therein comprises a stationary contact 21, a cooperating movable contact 23, asupporting metal frame indicated generally at 25, an operating mechanism indicated generally at 27 and a trip device indicated generally at 29.

The stationary contact 21 is welded, or otherwise attached, to a line terminal 31 which has a flange upper portion 32 (FIG. 4) that fits into a slot in the housing part 13. The line terminal 31 is held firmly in place by a stamped-out portion 33 that biases against a projection 34 that is molded integral with the housing part 13. A portion of the line terminal 31 protrudes through an opening 35 (FIG. 4) in the housing part 13. A similar portion of a symmetrically constructed line terminal 37 protrudes through an opening 39 in the housing part 11. Each of the line terminals 31 and 37 is a part of a separate independently functioning circuit interrupting unit. These terminals are resiliently biased to engage opposite sides of a contact member in a load center when the duplex circuit breaker is mounted in operating position.

The stationary contact 21 cooperates with a movable contact 23 that is welded or otherwise attached to a small flange 40 of a generally C-shaped contact or switch arm 41. Means for operating the switch arm 41 to the open and closed positions comprises an operating member indicated generally at 43 having a V-shaped opening 45 therein, which opening receives a projection 47 of the metallic frame 25. The operating member 43 is biased outwardly or upward as seen in FIGS. 13, by means to be hereinafter described, to a position wherein the lower edges of the projection 47 pivotally engage the lower side walls of the V-shaped opening 45. As can be best seen in FIG. 4, the switch arm 41 is bent over at its upper end at 48 and an opening 49 is stamped in the part 48. Depressions 51 are formed in the part 48 on opposite sides of the slot 49. When the parts are in operating position, a projection 53 molded integral with the operating member 43, extends into the slot 49 of the switch arm 41 to position the operating member 43 relative to the switch arm 41, and pivoting portions 55 on opposite sides of the projection 53 of the operating member 43 pivotally engage in the depressions 51 in the switch arm 41. The operating member 43 has a handle portion 57 molded integral therewith which extends through an opening 61 (FIGS. 1-3) in the housing whereby the mechanism may be manually operated to open and close the breaker. Arcuate surfaces 63 on opposite sides of the handle 57 substantially close the opening 61 in all positions of the operating member 43. Motion is transmitted from the operating member 43 to the switch arm 41 when the breaker is manually operated, and, from the switch arm 41 to the operating member 43 when the breaker is automatically tripped open.

The frame 25 supports an insulating pivot 65 (FIG. 4) having shoulders 67 at opposite ends thereof, which shoulders rest within a slot 69 in the frame 25 and a slot 71 in a projection 73 of the frame 25. A trip member 79 is pivotally supported at one end 77 by means of a bight portion which is pivotally supported in a slot 81 in the insulating pivot 65. The other end 82 of the trip member 79 has a latch point '83 which rests on a ledge on an armature 86 to support the trip member in latched position. The armature 86 is part of the trip device 29 which will be described later.

The ends 77 and 82 of the trip member 79 are offset, and disposed in a plane which is parallel to a plane in which the main body portion of the trip member 79 is disposed. A spring 88 (FIGS. 13) is connected, under tension, at one end in a slot 89 in the contact arm 41,

to the tripped position shown in FIG. 3.

and at the other end in a slot in a projection 93 extend-ing from the trip member 79.

The movable switch arm 41 is connected by means of a flexible shunt 95 (FIG. 1) to the free end of a bimetal 97 which is attached, near its other or upper end, to a projection 101 extending out from the supporting frame 25.

-A terminal conduct-or 103 is Welded or otherwise attached to the upper end of the bimetal 97 to electrically connect the bimetal to a load terminal structure that is indicated generally at 104. The closed circuit through the breaker extends from the line terminal 31 through the stationary and movable contacts 21, 23, the switch arm 41, the flexible shunt conductor 95, the bimetal element 97, the load terminal conductor 103 to the load terminal structure 104. Since the movable switch arm 41 extends downwardly from its pivot, the arc is established adjacent the bottom of the housing in an arc chamber 111, one end .of which is connected by a vent passage 113 to an opening in the end of the housing beneath the load terminal structure 104.

The circuit interrupting unit may be manually operated to open and close the contacts by operation of the insulating handle 57. Movement of the handle 57 clockwise, from the position shown in FIG. 1 to the position shown in FIG. 2, carries the upper end of the switch arm 41 to the left of the line of action of the spring 88 whereupon the spring acts to move the contact arm 41 with a snap action to" the open position shown in FIG. 2. A projection 109 molded integral with the housing acts as a limit stop for the movable contact arm during an opening operation. Movement of the operating handle 57 in a counterclockwise direction, from the position in which it is shown in FIG. 2, to the position in which it is shown in FIG. 1 moves the upper end of the switch arm to the right to move the parts to the closed position shown in FIG. 1. Movement of the handle 57 in either direction is limited by the surfaces 115 which strike the housing at either extreme position. The modified knife edge bearings of the projection 47 of the frame 25 within the opening 45 of the operating member 43, and of the pivoting portions 55 of the operating member 43 with the depressions 51 of the switch arm 41, encounter little friction and they, therefore, provide for a smooth operating type of mechanism.

1 The trip device 29 includes the bimetal 97, a U-shaped magnet 117, the armature 86 which is pivotally supported on the bimetal 97, and a spring 119 which biases the armature in a counterclockwise direction about its pivot. Upon the occurrence of an overload current below a predetermined value, the bimetal element 97 becomes heated, and when it is heated a predetermined amount it deflects to the right as seen in FIG. 1. Due to the engagement of a tail portion 121 of the armature 86 with the bimetal 97, the armature is carried to the right with the bimetal t to release the trip member 7 9.

Whenthe trip member'79 is released, the spring 88 acts to rotate it clockwise about its pivot 65 until his arrested when a stop portion 133 thereon strikes the projection 109 of the housing. During this movement, the line of action of the spring 88 moves to the right of the pivot 55, 51 of the switch arm 41, whereupon the spring biases the switch arm in opening direction and moves the switch arm so that the line of action of the force exerted by it on the operating member 43 shifts across the pivot 45, 47 and actuates the operating member 43 In order to provide a visual indication that the breaker has been automatically tripped open, movement of the operating member 43 is stopped in an intermediate position (FIG. 3) when a projection 135, molded integral with the operating member 43, strikes the projection 93 which extends from the trip member 79.

Positive separation of the contacts is assured during a tripping operation by the provision of a projection 137 extending from the trip member 79. If the contacts are slow in opening due to sticking, drag or other reasons,

the projection 137 engages the inner edge of the switch arm 41, with a swiping action, to start the switch arm in opening direction.

The interrupting unit is'trip-free in that it will automatically trip open even though the handle 57 is held in the closed position.

Before the contacts can be closed following an automatic opening operation, it is necessary to reset and relatch the mechanism. This is accomplished by moving the operating handle 57 clockwise from the tripped position (FIG. 3), slightly beyond the full open position (FIG. 2). During this movement, the projection of the operating member 43 engages with the projection 93 of the trip member 79, and the trip member is moved counterclockwise until the latch point 83 thereon is again supported in the latched position on the ledge of the armature 86, which position is shown in FIG. 2.

The circuit interrupting unit is tripped automatically and instantaneously by the electromagnet 97, 117, 86 in response to overload currents above the predetermined value. Upon the flow of current through the bimetal 97, a magnetic flux, which is induced around the bimetal, takes the path of least reluctance through the magnet 117, across an air gap 139, and through the armature 86. When an overload current above the predetermined value occurs, the pull of the magnetic flux is of such strength that the armature 86 is attracted to the magnet 17 and pivots in a clockwise direction about the bimetal 97. This movement releases the trip member 79, and the contacts are opened in the same manner previously described in connection with the thermal tripping operation. The features of the trip device 29 are specifically described and claimed in the aforementioned patents of Francis L. Gelzheiser, Patents Nos. 3,088,008 and 3,110,786. For this reason, only a brief description of the trip device is given herein.

Improved means are provided for venting the gases formed upon arc extinction. It was previously described with reference to FIG. 4, that the circuit breaker insulating housing comprises two parts 11 and 13 each composed of a back portion molded integral with four sides forming an open front. The interrupting unit housed by the housing part 13 is shown in FIGS. 1 and 2, and the interrupting unit housed by the housing part 11 is shown in FIG. 3. The back portion of the part 13, which is denoted by the reference character in FIGS. 1 and 2, therefore, acts as a barrier separating the two interrupting units of the circuit breaker. There is an opening 151 in the arc chamber portion of the barrier 150, and

three openings 153 in the vent passage portion 113 of the barrier 150. The openings 151 and 153 allow the gases which are formed upon arc extinction to pass from the arc chamber 111 and vent passage 113 of one of the interrupting units to the arc chamber 111 and vent passage 113 of the other interrupting unit. Since the two interrupting units of the duplex circuit breaker 9 operate independently, it can be understood that, generally, only one of them will trip or be operated to open at a time. Each interrupting unit, therefore, has the advantage of having a double arc chamber 111 and a double vent passage 113 from which to vent the arc gases which are formed when the interrupting unit is opened either automatically or manually.

Since numerous changes may be made in the abovedescribed construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all of the matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. I

I claim as my invention:

1. A circuit breaker comprising an insulating housing, said insulating housing comprising insulating barrier means separating said housing into two adjacent compartments, a separate circuit-breaker mechanism in each of said compartments, each of said mechanisms comprising a pair of contacts separable to establish an arc, each of said compartments comprising an arc-extinguishing and vent-passage area, said arc-extinguishing and vent-passage areas being separated by said barrier means, and opening means in said barrier means at said arc-extinguishing and vent-passage areas permitting passage of arc gases between said arc-extinguishing and vent passage areas.

2. A circuit breaker comprising an insulating housing, said insulating housing comprising insulating barrier means separating said housing into adjacent compartments, a separate circuit-breaker mechanism in each of said compartments, each of said separate mechanisms comprising a pair of contacts separable to establish an arc, each of said separate mechanisms comprising a separate manually operable means manually operable to open and close the associated contacts independent of the other of said separate mechanisms, each of said separate mechanisms comprising a separate trip means auto matically operable in response to overload currents above a predetermined amount to effect automatic opening of the associated contacts independent of the other of said separate mechanisms, each of said compartments comprising an arc-extinguishing and vent-passage area, each of said arc-extinguishing and vent-passage areas comprising an arc-extinguishing area in proximity to the associated contacts and a vent-passage area providing a vent passage from the associated arc-extinguishing area to the outside of said housing, said barrier means separating said arc-extinguishing and vent-passage areas, and opening means in said barrier means at said vent-passage areas permitting passage of arc gases between said vent-passage areas.

3. A circuit breaker comprising an insulating housing, said insulating housing comprising insulating barrier means separating said housing into adjacent compartments, a separate circuit-breaker mechanism in each of said compartments, each of said separate mechanisms comprising a stationary contact and a movable contact movable into and out of engagement with the associated stationary contact, each of said separate mechanisms com prising a separate manually operable means manually operable to open and close the associated contacts independent of the other of said separate mechanisms, each of said separate mechanisms comprising a separate trip means automatically operable in response to overload currents above a predetermined amount to elTect automatic opening of the associated contacts independent of the other of said separate mechanisms, each of said compartments comprising an arc-extinguishing area and vent means for venting gases from said arc-extinguishing area out of said housing, in each of said compartments the associated movable contact moving within the associated arc-extinguishing area, said barrier means being disposed, between said are-extinguishing areas, and gas-vent opening 'means in said barrier means in proximity to the paths of movement of said movable contacts at said arc-extinguishing areas to permit the passage of gases between said arc-extinguishing areas.

4. A circuit breaker comprising an insulating housing, said insulating housing comprising a front, a back, and sidewall means connecting said front and back, said sidewall means comprising a pair of sidewalls and a pair of end walls, common barrier means separating said housing into adjacent compartments with the opposite sidewalls of each of said compartments comprising a diiferent one of said sidewalls and said common barrier means, a separate circuit-breaker mechanism in each of said compartments, each of said mechanisms comprising a stationary contact and a movable contact movable into and out of engagement with the associated stationary contact, each of said stationary contacts being positioned in proximity to one of said end Walls, each of said compartments comprising an arc-extinguishing and vent-passage area, each of said arc-extinguishing and vent-passage areas compris ing an arc-extinguishing area in proximity to the associated contacts and a vent-passage area leading from the arc-extinguishing area and extending to opening means at the other end of said housing to vent gases out of said other end of said housing, and opening means in said common barrier means at said arc-extinguishing and ventpassage areas permitting passage of arc gases between said arc-extinguishing and vent-passage areas.

References Cited by the Examiner UNITED STATES PATENTS 3,018,351 1/1962 Middendorf 200-116 FOREIGN PATENTS 840,743 7/ 1960 Great Britain.

ROBERT K. SCI-IAEFER, Primary Examiner. ROBERT S. MACON, Examiner. 

1. A CIRCUIT BREAKER COMPRISING AN INSULATING HOUSING, SAID INSULATING HOUSING COMPRISING INSULATING BARRIER MEANS SEPARATING SAID HOUSING INTO TWO ADJACENT COMPARTMENTS, A SEPARATE CIRCUIT-BREAKER MECHANISM IN EACH OF SAID COMPARTMENTS, EACH OF SAID MECHANISMS COMPRISING A PAIR OF CONTACTS SEPARABLE TO ESTABLISH AN ARC, EACH OF SAID COMPARTMENTS COMPRISING AN ARC-EXTINGUISHING AND VENT-PASSAGE AREA, SAID ARC-EXTINGUISHING AND VENT-PASSAGE AREAS BEING SEPARATED BY SAID BARRIER MEANS, AND OPENING MEANS IN SAID BARRIER MEANS AT SAID ARC-EXTINGUISHING AND VENT-PASSAGE AREAS PERMITTING PASSAGE OF ARC GASES BETWEEN SAID ARC-EXTINGUISHING AND VENT PASSAGE AREAS. 